1. Field of the Invention
The present invention relates to an information display method by use of a card, which may be used, for example, as service card for shopping, which comprises an information display section comprising a reversible thermosensitive recording portion capable of recording information reversibly therein with application of heat thereto, in which information display section, first information can be stored successively and additionally, and second information indicating, for example, a valuable point value or premium to be gained by a customer, which is obtained, based on the first information and a reference information, can also be stored and displayed.
2. Discussion of Background
In most shops providing premium point service to customers, so-called customer's cards or members' cards are conventionally used. Such conventional members' cards mostly show very simple stamped information.
Telephone cards, prepaid cards for transportation, credit cards, cash cards for banks, and ID cards, which are now in general use, mostly record digital information for mechanical processing, and therefore do not have function of displaying recorded information in visible form. Therefore, there are many cases where hard copies which displays information recorded in such cards have to be made.
However, there are few that can provide recorded digital information in visible image in real time.
In an attempt to meet this requirement, there have been proposed IC cards with a built-in liquid display device using a thin battery so as to have a display function. These IC cards have such multiple functions that can be used as a calculator an well. However, they are costly due to the necessity for batteries and not always handy.
Japanese Laid-Open Patent Applications 4-242683 and 6-71039 disclose so-called point cards each comprising a stripe-shaped magnetic recording layer coated on the back side of the card. Furthermore, there is provided a visible image display portion on the front side of the stripe-shaped magnetic recording layer. In the visible image display portion, iron powder is sealed with a transparent sealing cover plate, and when the stripe-shaped magnetic recording layer in imagewise magnetized, the iron powder is correspondingly attracted imagewise to the imagewise magnetized portions of the stripe-shaped magnetic recording layer, whereby visible images made of the iron powder are formed by the magnetic powder. However, the thus formed magnetic power images are not suitable for use in practice.
There has not been available an the market a service card which in capable of reversibly recording information and displaying recorded information in visible form in real time and can be used in practice for an extended period of time.